Basically, the highly psychic eldar empire became completely consumed by hedonism to the point that a chaos god (Slaanesh) was born in the immaterium. This event created the eye of terror, a huge warp rift, which is a place where the real universe and the immaterium blend together
Do you actually have a point? Innocent children slain: bad. Evil leech that has a large part in oppressing us - maybe not so bad.
Do you really think the dude being white has anything to do with it? Pretty sure “CEO of health insurance company” is a sufficient descriptor and race has nothing to do with it